Dimensional Stability

The agricultural crop residuals are considered one of the most important problems, which face the environmental life and farmers in the world. The mechanical treatment by cutting, crushing or chopping and briquetting processes are the primary step and the suitable solution for solving this problem and recycling these residuals to be transformed into useful products. So the aim of the present work to get a high quality for agriculture residues such as date palm stalks, date palm leaflets briquettes. Chopped date palm stalks, date palm leaflets having moisture content (8, 10, and 12%) and (8, 10, and 12.8% w.b.) were densified into briquettes without binder and with binder (Urea-Formaldehyde) using a screw press machine. Quality properties for briquettes were durability, compression ratio hardness, bulk density, compression ratio, resiliency, water resistance and gases emission. The optimum quality properties found for briquettes at 8% moisture content and without binder. Where the highest compression stress and durability were 8.95, 10.39MPa and 97.06%, 93.64% for date palm stalks, date palm leaflets briquettes, respectively. The CO and CO 2 emissions for date palmstalks, date palm leaflets briquettes were less than these for loose residuals.

Resin-free fiberboards were manufactured using industrial fiber from Pinus radiata activated by an oxidative treatment using the Fenton reaction (H 2 O 2 / Fe(II)). A multivariate analysis was used to study the effect of fiber moisture content (MC), press temperature (T), and the H 2 O 2 /Fe(II) ratio on the board internal bond strength (IB). Using response surface methodology, a set of maximum IB conditions was obtained. Validation of these conditions which included 25% MC, 170ºC press temperature and a H 2 O 2 /Fe(II) relation of 25 produced an optimal board with an IB strength of 0.888 MPa. Without the addition of sizing agents or other additives, the dimensional stability properties were 16% of thickness swell and 40% of the water absorption of control boards.

Laminated object manufacturing (LOM) is a rapid prototyping process where a part is built sequentially from layers of paper. Studied in the present paper are the precision and accuracy of the LOM process and the dimensional stability of LOM parts. The process was found to exhibit both constant and random sources of error in the part dimensions. The dimensional error was the largest normal to the plane of the paper, exacerbated by the moisture absorption and subsequent swelling. The key process parameters were identified and optimized for sufficient bonding and cutting accuracy.

The production of paperboard covers the use of fiber in its structure and eventually coating layers. The production of paperboard by Klabin in Telêmaco Borba, specifically in the paper machine PM-9 produces boards with three layers from fiber obtained by kraft process pulp and high yield pulp, plus triple-layer coating that offers excellent printing characteristics for offset, flexography and gravure. One of the properties used to evaluate the print quality is mottling that describes the appearance of the marbled surface of the board. This property if out of the parameters of quality affects the final quality of the printed packaging, giving unpleasant appearance of older or that it had been stored at inappropriate place. Boards with this problem must be declassified, losing production or value and can generate customer complaints at expensive compensation. The mottling in this study was determined by the method Mottling STFI and is given by the coefficient of variation of reflectan...

Hybrid boards consisting of a strand core and particleboard faces (PSP) with three different shelling ratios were designed using strand sizes from dust to 4.5 mm mesh and normal particleboard face material. Flexural properties, internal bond (IB) strength, screw withdrawal resistance (SWR), hardness, and dimensional properties were measured. The modulus of elasticity of these hybrid boards was 25% greater than that specified by the ANSI standard for M3 industrial particleboard. An increase in modulus of rupture of approximately 50% was recorded for boards containing 60% strands compared with control particleboard without strands. Hybridization also accounted for a decrease in linear expansion compared with particleboard. However, IB strength decreased and SWR values showed no significant change. Therefore, with improved core properties, PSP has the potential to replace M3 particleboard.

Introduction Chapter 1 Properties Enhancement of Solid Wood by Cross-Linking Formation 1.1 Biological Resistance of Formaldehyde-Treated Wood 1.2 Biological Resistance of Wood Treated with Non-or Low-Formaldehyde Reagents 1.3 Weathering Properties of the Wood Modified with Cross-Linking Reagents Chapter 2 Application of Cross-Linking Formation to the Reconstituted Wood Products 2.1 Properties Enhancement of the Laminated Veneer Lumber (LVL) Modified with Some Cross-Linking Reagents 2.2 Dimensional Stability and Biological Resistance of Waferboard Treated with Cross-Linking Reagents 2.3 Hygroscopic Properties and Biological Resistance of Medium Density Fiberboard (MDF) Treated with Vaporous Formaldehyde Conclusion Acknowledgments References *1 This review article is the abstract of the Ph.D. thesis by the auther (Kyoto University, 1996) *

Chemically-modified laminated veneer lumbers (LVLs) were produced and their physical properties and biological resistance were evaluated. For the chemical modification, the vapor-phase formalization and the pad-dry-cure treatment ofveneers with some cross-linking agents were employed prior to lamination of the treated veneers. The vapor-phase formalization was conducted for 5, 10 and 24 hours using tetraoxane as a source offormaldehyde, and the pad-dry-cure treatments with glutaraldehyde and dimethylol dihydroxy ethylene urea (DMDHEU) were made after impregnation of their 2.5,5 and 10% aqueous solutions. Sulfur dioxide was used as a catalyst in both treatments. Laboratory tests with a brown-rot and a white-rot fungus revealed that decay was almost completely suppressed at the high levels of treatment, and fairly eliminated at the low levels of treatment. The treatment could reduce the weight loss of specimens caused by termite attack, but the effectiveness in resisting it was not as sufficient as was decay resistance. All treated LVLs were very stable to water soaking even in the 2-hour boiling on thickness swelling as well as linear expansion along tangential direction.

La gestión/disposición final de la coronta de maíz (CM) constituye un desafío a nivel global, debido a los elevados volúmenes de generación y su escaso aprovechamiento. Dentro del desarrollo de materiales, las
características de este residuo permiten su uso como refuerzo en composites. El presente estudio tiene como finalidad la elaboración y caracterización de biocomposites con refuerzo de CM en matriz de copolímero vinil acrílico (CVA). Para el efecto, se molieron las CM, se tamizaron en dos tamaños de partícula (2.00 y 1.18 mm), y se mezclaron con resina base-acuosa de CVA. La mezcla se prensó a 80 y 120 °C para obtener láminas de 2.05 ± 0.05 mm de espesor. El análisis estadístico identificó que las características de tracción se ven influenciadas por la interacción entre el tamaño de partícula y temperatura de procesamiento. Los resultados del comportamiento mecánico evidenciaron un incremento del módulo de elasticidad en comparación con el CVA solo. Los refuerzos de 2.00 mm presentaron mayor ductibilidad, mientras que una temperatura de 120 °C, incrementó la rigidez del biocomposite.
Complementariamente, se analizó el comportamiento térmico y los grupos funcionales por espectroscopía infrarroja. La calorimetría diferencial de barrido evidenció un aumento de la temperatura de transición vítrea del CVA, mientras que el análisis termogravimétrico presentó una disminución de la cinética de las reacciones térmicas de
descomposición de la CM. La espectroscopía confirmó mayor presencia de CVA. Los resultados globales sugieren interacciones fuertes matriz-refuerzo, una función protectora de la matriz y su efectivo recubrimiento e imbibición en los refuerzos.

The aim of this study was to determine and compare the linear dimensional changes, and water sorption of a denture base polymer reinforced with chopped glass fiber and metal filler. The dimensional changes were measured immediately after processing, after 1, 2, 3, 7 and 14 days of water storage. The results revealed that both types of reinforcement affect the dimensional accuracy and water sorption of the test specimens. The greatest dimensional accuracy was found with the glass fiber reinforced test specimens. The lowest amount of water sorption was found with the metal-filled test specimens. It was concluded that, metal fillers decreased the water sorption of the resin material greater than the effect of glass fibers, while the glass fibers showed marked reduction in the linear dimensional changes of acrylic resin than that of the metal fillers. The glass fibers and metal fillers can be clinically used as a denture base reinforcement.

Since its inception, the Geographic Information System (GIS) has been widely used in many areas of the civilian sector. However, this system with its remarkable technical capabilities is still insufficiently implemented in the military sphere. Therefore, the article points out the necessity and expediency of creating a GIS for military purposes. When creating a GIS for military purposes, it should enrich its main block, that is, a topographic database (TDB) with additional materials such as special maps, aerospace photo documents that are universally used in the troops.Based on these considerations, the article proposes to create in the military GIS an additional functional unit called the "Special Map Base". This article describes in detail the structure, content and function of the proposed block.

Hydrothermal carbonization (HTC) is a chemical pretreatment of wood waste for convert it in biochar by the application of high temperatures and pressures in a reaction time that do not exceed 10 hours. One of the main applications of the HTC biochar is as pellets. In this research durability against fungal decay and dimensional stability associated with relative humidity changes of HTC pellets were analyzed and evaluated. A comparison of these properties between HTC pellets and wooden EN+ pellets has been carried out. HTC pellets are significantly more durable against fungal attack, more dimensionally stable against relative humidity changes and denser than wood pellets, which confers better properties for logistics processes like storage and transport.

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This paper presents a design of a variable size spatial filter used in the wavefront sensor subsystem of the Gemini Planet Imager instrument. It describes an adjustable mechanism consisting of two slides forming a square aperture which can be varied in size between 1.8 and 6.7 mm. These slides are located on athermalized flexure mounts that move opposite to one another driven by a single precision linear actuator. The device retains long term dimensional stability, resolution, and repeatability on a micron level for all gravity vector orientations and for temperatures between -5°C and + 25°C.

The SORGENTINA-RF project aims to develop a 14 MeV fusion neutron source to produce medical radioisotopes with special focus on $$^{99}$$ 99 Mo. The facility is based on a positive ion source with an acceleration stage to produce a deuterium (D$$^{+})$$ + ) and tritium (T$$^{+})$$ + ) ion beam that, impacting on a titanium-coated rotating target, allows fusion reactions to take place. Maximizing the neutron production rate is one of the main issues to be addressed in the project and the optimization of some key parameters of the ion beam is of paramount importance in this regard. In this study, a methodology is discussed to reach a definition of the beam characteristics for an effective and sustainable operation of the plant. The most convenient layout that has been found out is based on a single ion source fed by a deuterium and tritium gas mixture. Eventually, a series of considerations about the operation of the ion source and fuel cycle have been drawn.

The available thermal conductivity data for various neutron-irradiated 2-3 dimensional carbon fibre composite materials have been collected and have been critically reviewed with respect to possible application in the ITER divertor. The empirical correlations are proposed that match the thermal conductivity data and allow interpolate or extrapolate of the behaviour in the wide temperature ($150-3000 °C) and fluence (0-0.1 dpa) ranges of interest for ITER. These include the correlations for materials with 'high' ( J 200 W/m K) initial thermal conductivity and for materials with moderate ($100 W/m K) thermal conductivity. Using the proposed formula the thermal performance of CFC armoured ITER divertor is assessed.

Wood is a natural porous fibre composite, which has some structural similarities to bone. Recently, it has been used as a modelling material in developing synthetic fibre-reinforced composite to be used as load-bearing non-metallic artificial bone material. In this study, the behaviour of wood implanted into bone was studied in vivo in the femur bone of the rabbit. Wood was pre-treated by heat, which altered its chemical composition and structure, as well as the biomechanical properties. In the heat treatment, wood's dimensional stability is enhanced, equilibrium moisture content reduces and the biological durability increases. Cone-shaped implants were manufactured from heat-treated (at 200 and 140 °C) birch wood (Betula pubescens) and from untreated birch. A total of 62 implants were placed in the distal femur of 50 white New Zealand rabbits. The behaviour of the implants was studied at 4, 8 and 20 weeks with histological and histometrical analysis. Osteoconductive contact line and the presence of fibrous tissue and foreign body reaction were determined. The amount of fibrous tissue diminished with time, and the absence of foreign body reaction was found to be in correlation to the amount of heat treatment. Histologically found contact between the implant and the host bone at the interface was significantly more abundant in the 200 °C group (avg. 12.8%) vs. the 140 °C (avg. 2.7%) and the untreated groups (avg. 0.6%). It was observed that the heat treatment significantly modified the biological behaviour of the implanted wood. The changes of the wood by heat treatment showed a positive outcome concerning osteoconductivity of the material.

The next generation microprocessor assemblies will require integrated thermal management design solutions as the device density and clock speeds increase. These solutions will include a heat spreader, or lid, that is in contact with the heat generating microprocessor in the total packaging assembly. The materials choice for these integrated heat spreader solutions must provide the following material property attributes. • High bulk thermal conductivity • CTE compatibility with the Device and/or Microprocessor Assembly • EMI/RFI Shielding • Light weight • Dimensional Stability/Flatness (minimize bond line length resulting in a decreased Θ JC ). • Competitive Pricing AlSiC, Aluminum Silicon Carbide, metal matrix composite materials meet the material property, design and pricing demands for microprocessor assemblies that require integrated heat sink thermal management solutions. The CTE of AlSiC material and components can be tuned to be compatible with the specific heatsink application by controlling the SiC volume fraction in the AlSiC composite. AlSiC products with CTE values 7 -9 ppm/°C (30 -250°C) are suitable for direct attachment to GaAs and Si devices and ceramic substrate. Higher CTE materials 10 -12 ppm/°C are used for attachment to printed circuit boards. The AlSiC thermal conductivity value is 180 -200 W/mK (compositional dependent) similar to CuMo and CuW materials. The material density of AlSiC is 1/3 rd to 1/5 th that of CuMo and CuW making AlSiC more suited to weight sensitive applications. The Ceramics Process Systems AlSiC components are cost-effectively fabricated to net-shape attaining close dimensional tolerances with minimal machining. The AlSiC material composition (hence CTE) is controlled by monitoring the SiC volume fraction of a tightly toleranced SiC preform fabricated with the QuickSet™ injection molding process. The pore structure of the SiC preform is infiltrated with molten Almetal (termed the QuickCast™ process) to form the AlSiC composite material to the exact product dimensions defined by the infiltration mold. The combined processes form a fully dense, hermetic material of discrete SiC particulate in a continuous Al-metal matrix phase. This process is currently used for high volume production for a number of product geometries and thermal management applications including MPU integrated heat spreading lid solutions. The ideal material properties coupled with AlSiC fabrication process provide low-cost highperformance functional integrated thermal management heat spreading solutions for microprocessor applications. This paper will illustrate the AlSiC material/design capabilities through microprocessor heat spreader examples.

RESUMO: LSL (laminated strand lumber) e OSL (oriented strand lumber) são compostos estruturais recentemente introduzidos no mercado dos países que, tradicionalmente, empregam a madeira na construção civil. Surgiram como uma alternativa ao uso de madeira maciça, tendo em vista sua escassez. Objetivou-se, principalmente, neste estudo verificar o efeito do uso de partículas com diferentes comprimentos nas propriedades físicas e mecânicas desse tipo de painel. Foram produzidos seis painéis utilizando-se partículas de 15 cm (oriented strand lumber -OSL) e 30 cm (laminated strand lumber -LSL), produzidas a partir de lâminas de Chrysophyllum sp. Foram determinadas as propriedades de flexão estática (MOE// e MOR//), compressão paralela (COMP//), inchamento em espessura (IE), absorção de água (AA) e expansão lateral (EL) após 2 e 24 horas de imersão em água, segundo a norma ASTM D5456 (ASTM, 2006). As propriedades de resistência foram comparadas com as da madeira sólida. Foi feita também avaliação não-destrutiva das propriedades de flexão por meio da técnica de ondas de tensão. Os resultados obtidos indicaram que não houve diferença significativa entre OSL e LSL, para as propriedades mecânicas. No entanto, para as propriedades físicas, o OSL apresentou-se com maior estabilidade dimensional, dados os menores valores de IE, AA e EL. Quando comparados à madeira sólida de Chrysophyllum sp., os painéis OSL e LSL obtiveram valores de resistência mecânica próximos, mas estatisticamente inferiores. Palavras-chave: LSL, OSL, propriedades físicas e mecânicas, geometria das partículas.

The Rosenberg Self-Esteem Scale (RSES) was adapted to the Estonian language. By all relevant psychometric properties the developed Estonian version of the Rosenberg Self-Esteem Scale (ERSES) was identical to the original construct measuring a person's overall evaluation of his or her worthiness as a human being. Both exploratory and con®rmatory factor analyses revealed that global self-esteem can be best represented as a single dimension. The temporal stability of the ERSES was also very similar to the original version demonstrating an exponential decay over time. Like previously reported ®ndings, individuals with high self-esteem tended to obtain similar and individuals with low self-esteem divergent total self-esteem scores on two subsequent occasions. A joint factor analysis of the ERSES and the Revised NEO Personality Inventory (NEO-PI-R) scales led to a ®ve-factor structure which replicated the normative North-American structure, self-esteem loading signi®cantly only on the Neuroticism factor. The pattern of correlations between the ERSES and the Five-Factor model of personality dimensions was very similar to that obtained in Hong Kong and Canada [Kwan, V. S. Y, Bond, M. H., & Singelis, T. M. (1997). Pancultural explanations for life satisfaction: adding relationship harmony to self-esteem. Journal of Personality and Social Psychology, 73, 1038±1051] suggesting that the relationship between personality and self-esteem is universal, not depending on a particular language and/or culture. The correlations between the ERSES and two other personality measures, the Self-Consciousness Scale (SCS) and the Self-Concept Clarity Scale (SCCS), also supported cross-cultural generalizability of the relationships between personality and self-esteem.

Th e purpose of this study was to improve some physical properties of particleboard using chitosan treatment. Particleboard is a main product for furniture industry and also used as a home decoration material in Turkey; however, it has a poor dimensional stability. In this study, wood particles, which were obtained from a commercial plant, were treated with chitosan acetate solutions (2% wt). Treated particles before the assembly also had extra high-heat treatment to convert insoluble chitosan acetate fi lm over the particles to insoluble chitin. Diff erent time intervals and temperature regimes were used in this experiment to select suitable temperature and time for chitosan acetate conversion to chitin. 6% liquid phenol-formaldehyde resin was used based upon oven-dry weight. Th e mat was pressed at 200°C for 8 minutes to form 1.2 cm thick and a target of 0.66 g.cm-3 density panel. Physical properties of the chitosan treated particleboards were improved; thickness swelling and wate...

In this study, a simple and efficient preparation method of wood-plastic composites (WPC) from maple wood flour (filler) and high-density polyethylene (HDPE) through extrusion was conducted, and the effects of low concentration (2% w/w) coupling agent addition (maleated polyethylene, MAPE) on their physical and mechanical properties were tested. Tensile test, dimensional stability (water absorption) test, melt flow rate test, and differential scanning calorimetry (DSC) analysis were utilized to assess the physicomechanical properties of the finished composite products. The tensile test quantified the ability of the materials to withstand pulling forces and resulting deformation before breakage. An improvement in stiffness and resistance to breaking under stress was observed. There was a statistically significant difference between WPC and WPC+MAPE in terms of flexural strength and modulus (p < 0.05) but no statistically significant difference between the same samples in terms of strain at breakage (p > 0.05). There was also no observed difference in the melt flow rate and enthalpy functions of WPC and WPC+MAPE. The minimal addition of a coupling agent (MAPE) to WPC significantly improved dimensional stability, as evidenced by 13% lower thickness swelling and 3% lower mass gain through water absorption.

This work presents a comparative study of the surface characteristics of spur gears produced from cryotreated and untreated hobs at various cutting speeds and feed rates keeping constant depth of cut. Furthermore, a Taguchi Grey Relational Analysis was used to optimize the hobbing process and ANOVA was conducted to analyze the influence of studied parameters. The experimental run, for which the highest gray relational grade was obtained, was considered the optimal cutting condition. The results revealed that cryogenic treatment of the hob significantly decreased the spur gear's flank surface roughness (R a andR max) and microgeometric deviations (F a; F β ; F p andF r). The optimization results revealed that a cutting speed of 400 rpm and a feed of 8 mm/min with a cryo-treated hob produced the best surface characteristics (i.e.R a ¼ 0:30μ m; R max ¼ 2:77μ m; F a ¼ 10:60μ m; F β ¼ 20:03μ m; F p ¼ 10:40μ mandF r ¼ 20:20μ m). This study can assist manufacturing industries in selecting suitable operating parameters for obtaining highquality gears.

This study aimed to (i) characterize municipal solid waste (MSW) sourced from Utah and Michigan transfer stations and (ii) upcycle, produce, and evaluate composites derived from this MSW. Composition analysis showed that the MSW was composed of a variety of commodity plastics, paper/cardboard, and inorganic materials. Detailed chemical analysis for lignin, cellulose, hemicellulose, and lipids was performed. The plastics identified were mainly polyethylene, polypropylene, polystyrene, and poly (ethylene terephthalate). The compoundability of the MSW was assessed by torque rheometry. Composites were prepared by compounding the MSW in an extruder. A composite flexural strength of 29 MPa and a modulus of 1.0 GPa was achieved. The thermal properties of the composites were also determined. The melt flow behavior of the MSW composites at 190 • C was comparable to wood plastic composite formulations.

This study was initiated to investigate the effect of presteaming on drying stresses of red oak ( Quercus sp.) using the coating and bending method. Besides the presteaming effect, a directional effect on drying stresses was also tested. Four blocks were randomly selected. Each block was divided into two pairs (four samples). One pair was randomly assigned to steaming while the other was assigned to control. A statistical split-plot model was used to analyze the results. Presteaming increased drying stress by up to 36% and decreased drying time by 23% when red oak was dried at 75% relative humidity and 44 C from average moisture content of 80 to 16%. The maximum drying stress of the steamed samples occurred before that of the unsteamed samples due to faster moisture loss from the sample. This study indicated that the coating and bending method could be used to study drying stresses of red oak. The statistical model revealed the differences between steaming and control and between in...

Various physical changes causes alterations in the fit of the denture. Since most of the recipients of the complete denture prosthesis are the geriatric population,a time saving procedure is paramount for the satisfaction of the patient. Thus the need for dimensionally accurate relining and rebasing was established . This study estimates the changes in the linear dimensions of 28 dentures before and after relining and rebasing. Two groups with 14 dentures each for relining and rebasing were selected .Pre reline and pre-rebase measurements were recorded .Impressions were recorded using closed mouth technique. Post reline and post rebase measurements were recorded. The collected data was statistically compared and analyzed. Statistically significant variation was seen in change of dimensions comparing reline and rebase. The dimensional differences between pre and post reline/rebase did not hinder the attained support and retention of the denture. Relined and rebased dentures had negligible variations.

A Ti 49.5 Ni 25 Pd 25 Sc 0.5 high-temperature shape memory alloy is thermomechanically processed to obtain enhanced shape-memory characteristics: in particular, dimensional stability upon repeated thermal cycles under constant loads. This is accomplished using severe plastic deformation via equal channel angular extrusion (ECAE) and post-processing annealing heat treatments. The results of the thermomechanical experiments reveal that the processed materials display enhanced shape memory response, exhibiting higher recoverable transformation and reduced irrecoverable strain levels upon thermal cycling compared with the unprocessed material. This improvement is attributed to the increased strength and resistance of the material against defect generation upon phase transformation as a result of the microstructural refinement due to the ECAE process, as supported by the electron microscopy observations.

Bamboo (Phyllostachys bambusoides Sieb et Zucc.) particales were acetylated with acetic anhy dride along, and the acetylated particles were pressed into particleboards using a phenolformalde hyde adhesive. In liquid-water tests, boards made from acetylated particles swelled at a much slower rate and to a less extent than did control boards after 5 cycles of wetting and oven drying. In humidity tests, all boards made from acetylated particles had much lower equilibrium moisture contents than the control boards.

The thesis investigates optical measuring and statistical data processing, and presents a method to understand and reduce sawing variation by examination of sawn timber sizes. Continuous timber size control offers improved opportunities for analysing saw machines or even individual sawblades. The thesis is illustrated with seven saw machine case studies that relate to the development of the technique. Log and cant breakdown is examined in single-and double-arbor circular saws and bandsaws. The first analysis of each saw machine is made in normal production, and the second using a controlled benchmarking test. A total of 44350 logs were sawn in the study. The behaviour of a saw machine is described using such descriptors as total, within-board and between-board standard deviations, and sawblade bend. Based on observations in benchmarking, an equation y=αe βx ±R, where α and β are constants, R the process reproducibility, and x a variable that expresses sawing time and saw load, can be established for each of the saw machine descriptors. An example is the total standard deviation descriptor function s=0.21e 0.58x ±0.11, established for a single-arbor circular saw in a 4-piece saw set-up. The method will help a sawmill to establish descriptors and equations used to describe the behaviour of their saw machines, to baseline saw machine performance and to compare it to best practices in the industry. The descriptors may be used to establish current, short-or long-term capabilities and characteristics. The method can be used to examine various production conditions and tooling, such as effects of log size, feed speed, and sawing time. Other factors include saw speed, sawblade parameters, operation of setworks and feedworks, and effects of seasons. The results of the study show that sawblade behaviour, feedworks and work piece holding problems, and previous saw machines may be causes of large sawing variation.

Curve sawing is a primary log breakdown process that incorporates gang-saw technology to allow two-sided cants from logs with sweep to be cut parallel to the log surface or log axis. Since curve-sawn logs with sweep are cut along the grain, the potential for producing high quality straight-grain lumber and cants increases, and strength, stiffness, and dimensional stability are maxi- mized. Presently, curve sawing methods are widely incorporated in high production softwood lumber manufacturing facilities. However, with a few exceptions, the practice of curve sawing is virtually nonexistent in hardwood sawmills. A previous study indicated that approximately one-third of hardwood sawlogs contain measurable sweep. The purpose of this study was to investigate the impact of sawing pattern (straight vs. curve sawing) on lumber, cant, and pallet part yield from small-diameter hardwood logs with varying degrees of sweep. The results of this study indicate that cant and pallet part yields are...

Resumo: O objetivo deste trabalho foi investigar por meio de métodos estatísticos as propriedades de rigidez (E c0 e MOE) e de resistência (f c0 , MOR, f t0 e f v0 ) da madeira Eucaliptos citriodora após sua termorretificação nas temperaturas: 160, 180, 200, 220 e 240 em graus Celsius com relação à madeira em temperatura ambiente (in natura). Foram considerados os resultados dos ensaios experimentais de resistência e de rigidez obtidos por Silva (2012), sendo que estes resultados foram analisados por meio do pacote estatístico comercial "R", versão 3.0.1. Os resultados do ajuste do modelo multivariado de análise de variância (MANOVA) e dos testes de Tukey mostraram que a termorretificação da madeira não apresentou significativas influências na rigidez da madeira, entretanto com relação à resistência da madeira foi identificada uma significativa queda dessa propriedade, principalmente nas amostras tratadas nas temperaturas: 220º C e 240º C. Tanto na análise de componentes principais e como na análise de agrupamentos robustas foram identificas amostras multivariadas anômalas, entretanto tais amostras não afetaram as conclusões finais do estudo.

During the drying stage of the papermaking process, paper undergoes dimensional changes caused by fiber dehydration, but exhibiting uneven width reduction magnitudes along the cross-machine direction. The degree of cross-direction (CD) shrinkage can be very different at the edges when compared to the center of the web. The highest shrinkage amplitude at the web edges can vary according to the operation conditions and the drying section configuration as well. The difference in the degree of CD shrinkage gives rise to adverse effects on the finished CD paper sheet properties, particularly strength and hygroelastic properties, which can vary many percents from the edges to the center of the web. Extreme property values lead to different problems, such as sheet differential dimensional instability, which can limit paper quality and converting efficiency, especially in high speed machines (e.g., multicolor offset printing and office copier machines). The issues considered above make clear the advantages of measuring and carefully analyzing the differential CD shrinkage profile of finished paper. This work reviews the CD differential shrinkage profile development in the drying section, its impact on finished paper properties and presents an accurate and low cost measurement method based on image analysis techniques, supported by digital processing through the two-dimensional Fast Fourier Transform (2D-FFT). The experimental results show that image analysis applied to paper samples taken from the jumbo roll represents a reliable method for determining the differential CD shrinkage profile, and a practical tool for monitoring paper quality and evaluating its CD dimensional stability profile.

During the drying stage of the papermaking process, paper undergoes dimensional changes caused by fiber dehydration, but exhibiting uneven width reduction magnitudes along the cross-machine direction. The degree of cross-direction (CD) shrinkage can be very different at the edges when compared to the center of the web. The highest shrinkage amplitude at the web edges can vary according to the operation conditions and the drying section configuration as well. The difference in the degree of CD shrinkage gives rise to adverse effects on the finished CD paper sheet properties, particularly strength and hygroelastic properties, which can vary many percents from the edges to the center of the web. Extreme property values lead to different problems, such as sheet differential dimensional instability, which can limit paper quality and converting efficiency, especially in high speed machines (e.g., multicolor offset printing and office copier machines). The issues considered above make clear the advantages of measuring and carefully analyzing the differential CD shrinkage profile of finished paper. This work reviews the CD differential shrinkage profile development in the drying section, its impact on finished paper properties and presents an accurate and low cost measurement method based on image analysis techniques, supported by digital processing through the two-dimensional Fast Fourier Transform (2D-FFT). The experimental results show that image analysis applied to paper samples taken from the jumbo roll represents a reliable method for determining the differential CD shrinkage profile, and a practical tool for monitoring paper quality and evaluating its CD dimensional stability profile.

Purpose: The aim of this paper was to analyze the influence of incorporation of disinfectants during the die stone linear expansion. Materials and Methods: Die stone type IV specimens with disinfection solutions (sodium hypochlorite 1%, chlorhexidine 2%) were incorporated in two concentrations (50%, 100%). The dimensional stability was tested in accordance with ADA recommendations. Results: Addition of undiluted sodium hypochlorite determines the significant reduction of expansion setting, in a percentage more important than diluted chlorhexidine. Conclusions: Use of undiluted hypochlorite negatively affects the model sizes, while using 50% dilution or 50 or 100% chlorhexidine did not significantly alter its stability.

Scots pine wood (Pinus sylvestris L.) was submitted for controlled decay using two testing fungi species causing: brown-rot decay (Coniophora puteana (Schum.: Fr.) P. Karst.) and whiterot decay (Trametes versicolor (L.: Fr.) Pilát). The influence of fungi activity on wood chemical composition changes was examined. Trametes versicolor fungus (white-rot) simultaneously decomposes all of wood structural components – cellulose, hemicelluloses and lignin. The rate of cellulose and lignin content decrease is similar. Brown-rot decay does not cause lignin decomposition, only carbohydrates decompose. Fast cellulose decomposition takes place. Its rate is higher than wood mass-loss indicates. Research presented in this paper allows finding the correlation between the mass-loss of wood decayed by given fungus species and structural wood components content.

This project addresses the following technical barriers from the Fuel Cells section of the Hydrogen, Fuel Cells and Infrastructure Technologies Program Multi-Year Research, Development and Demonstration Plan: • C. Thermal Management • F. Heat Utilization • L. Hydrogen Production/Carbon Monoxide Clean-up • M. Fuel Processor System Integration and Efficiency • N. Cost • O. Stack Material and Manufacturing Cost • P. Durability • Q. Electrode Performance • R. Thermal and Water Transport

Future directions will focus on additional methods of reinforcing and cross linking SPEKK membranes in anticipation of improving the durability of the MEAs. Additional work will be required beyond the scope of this funding to optimize the durability of SPEKK based-MEAs and should include: • Synthesis of a new grade of polyether ketone ketone that is optimized for improved membrane durability and maximized conductivity. • Improve fabrication techniques for polymer blends, reinforced composites, and cross linked structures to further improve durability.

This study examined the effect of medium density fiberboard (MDF) density and moisture content on MDF moduli of elasticity E1, E3, shear modulus, G13, and Poisson&#x27;s ratios � 12 and � 13. The relation of all pa- rameters with density was determined from MDF panels without density profile with average density lev- els of 540 kg/m3, 650 kg/m3, and 800 kg/m3. The relation with moisture content was determined from specimens conditioned to 50%, 65%, and 80% relative humidity. Panel E1, E3, and G13 increased with den- sity increase and decreased with moisture conent increase. At each nominal density level, the values of E1 were much higher than the values of G13, which in turn were higher than the values of E3. The effect of density and moisture content on the Poisson&#x27;s ratios was not significant.

Department of Energy to conduct research focused on resolving the key technical issues that limited the deployment of efficient and extremely compact microtechnology based heat actuated absorption heat pumps and gas absorbers. Success in demonstrating these technologies will reduce the main barriers to the deployment of a technology that can significantly reduce energy consumption in the building, automotive and industrial sectors while providing a technology that can improve our ability to sequester CO 2 . The proposed research cost $939,477. $539,477 of the proposed amount funded research conducted at OSU while the balance ($400,000) was used at PNNL. The project lasted 42 months and started in April 2001. Recent developments at the Pacific Northwest National Laboratory and Oregon State University suggest that the performance of absorption and desorption systems can be significantly enhanced by the use of an ultra-thin film gas/liquid contactor. This device employs microtechnology-based structures to mechanically constrain the gas/liquid interface. This technology can be used to form very thin liquid films with a film thickness less then 100 microns while still allowing gas/liquid contact. According to the 1997 Residential Energy Consumption Survey (RECS), 56.6 million households were served by central (ducted) warm-air furnace systems. These systems consumed 3.31 Quads of energy (mostly natural gas and fuel oil) at a cost of $24.53 billion. The efficiency of a typical central furnace is assumed to be about 80%, while the Coefficient of Performance (COP) of an absorption heat pump is estimated to be about 1.2. Thus, the 25% savings associated with ducting losses, etc., coupled with the increase in equipment efficiency would combine to cut energy use in half, resulting in energy savings of 1.66 Quads valued at $12.26 billion per year. Central (ducted) heat pumps provided heating for 9.7 million households according to the 1997 RECS. These electrically-driven devices consumed 0.13 Quads (measured at the site) at a cost of $2.64 billion. According to figures presented in the 1997 Annual Energy Review, the combined conversion, transmission, and distribution efficiency for electricity was 30%. Thus, 0.13 Quads at the site is equivalent to 0.43 Quads at the source. Assuming a COP of 2.5 for an electrically-driven heat pump (compared to a COP of 1.2 for the absorption heat pump) and 25% savings for reduced ducting losses, etc., site energy use would increase from 0.13 Quads to 0.20 Quads. The absorption heat pump is not electrically-driven; so site and source energy are the same. Thus, the net source energy savings are 0.23 Quads per year. The cost of 0.20 Quads of fossil energy in the residential sector (based on RECS data for space heating) would be $1.50 billion, resulting in net energy dollar savings of $1.14 billion per year. Central (ducted) air conditioning systems (via heat pumps or AC only systems) were used in 47.5 million households according to the 1997 RECS, consuming 0.34 Quads of electricity (measured at the site) at a cost of $8.26 billion. This is equivalent to 1.13 Quads of source energy when energy electricity generation, transmission, and distribution losses are included. The absorption heat pump COP is only expected to be 0.65 in the cooling mode, compared to an assumed COP of 2.5 for the electrically-driven heat pump. Nevertheless, when coupled with 25% load savings for reduced ducting losses, etc., source energy consumption for the absorption heat pump is only 0.98 Quads, resulting in annual energy savings of 0.15 Quads. The 0.98 Quads of fossil energy is estimated to cost $7.26 billion in the residential sector (based on RECS data for space heating), resulting in annual dollar savings of $1.0 billion. The combined annual savings for central (ducted) heating and cooling systems are 2.04 Quads (source energy) and $14.4 billion. Site energy savings were estimated to be 0.47 Quads of electricity and 0.48 Quads of fossil energy. The latter is roughly 80% natural gas and 20% fuel oil. Air conditioning of automobiles is currently accomplished with vapor compression devices that are driven by shaft power generated by the auto's engine. With an IC engine efficiency of about 20% and an automotive vapor compression COP of 0.8, overall efficiency is poor. Absorption coolers offer significant performance improvement by avoiding the inefficiencies of IC engine shaft power. Conventional absorption-based cooling systems are too bulky for the automotive application, however, so development of a compact absorption cooling system is required to take advantage of the efficiency improvement opportunity. According to the Transportation Energy Data Book (Davis 1998), 130 million cars were driven 1.47 trillion miles or an average of 11,314 miles per car. The average speeds for the federal urban and highway driving cycles are 20 mph and 50 mph, respectively. Assuming that half of the annual mileage is accumulated at the urban rate and half at the highway rate, the total annual driving hours would be about 400. The number of air-conditioned driving hours would depend on climate and typical driving schedules. Lacking better data, air conditioning was assumed to be required half of the time. A passenger car cooling system is commonly sized to provide up to 2 tons (24,000 Btu/hour) of cooling. The cooling unit operates at capacity when bringing a car down from a "hot soak" condition to a comfortable operating temperature. At steady-state the required cooling capacity is much lower. This analysis assumes the air conditioner operates at full capacity for 20% of the cooling hours, but only 20% of capacity for the rest of the cooling hours, for an average capacity factor of 0.36 or average capacity of 0.72 tons or 8640 Btu/hour. Thus, the annual average cooling load served by the air conditioning system is 1.728 MMBtu With an IC engine efficiency of 0.20 and vapor compression COP of 0.8, the conventional automotive AC system consumes 10.8 MMBtu/year in the form of gasoline. The absorption cooler COP is estimated to be 0.5 in the automotive application. Its COP for the automotive application is less than for the space cooling application because the automotive condensing temperatures are generally higher. Although IC engine waste heat could provide part of the thermal input to the absorption cooler, the quantity available is not always adequate. This analysis assumes that all of the thermal input for the absorption cooler comes from combusting gasoline in a micro-channel combustor at an efficiency of 80% (i.e., 80% of the fuel's chemical energy is converted and transferred to the absorption cooler). Thus, the annual energy consumption for the absorption cooler is 4.32 MMBtu/year or a savings of 6.48 MMBtu/year. This is equivalent to 52 gallons of gasoline per year or a dollar savings of about $78 per year. If applied to the population of automobiles (130 million passenger cars), the total annual savings would be 0.84 Quads and $10.1 billion.. These figures do not include the potential impact of 69 million light trucks (pickups, vans, and utility vehicles). Nor do these figures consider the potential impact of enabling air conditioning in future electric, fuel cell, or hybrid vehicles where the shaft power demand of a conventional vapor compression unit would be a significant burden.

The aim of this study was to determine and compare the dimensional changes of polyether and vinyl polyether siloxane impression materials under immersion disinfection with two different disinfectants in three time periods. Impressions were obtained from an edentulous master model. Sodium hypochlorite (5.25%) and glutaraldehyde (2%) were used for disinfection and measurements were done 30 min later after making impression before disinfection, after required disinfection period (10 min), and after 24 h storage at room temperature. Impressions were scanned using 3D scanner with 10 microns accuracy and 3D software was used to evaluate the dimensional changes with superimpositioning. Positive and negative deviations were calculated and compared with master model. There was no significant difference between two elastomeric impression materials (p>0.05). It was concluded that dimensional accuracy and stability of two impression materials were excellent and similar.

In this study, the eff ect of treatment time on dimensional stability, moisture content, and mechanical properties of heat-treated Anatolian chestnut (Castanea sativa Mill.) were investigated. Test specimens were subjected to a temperature of 180°C at atmospheric pressure for fi ve diff erent treatment times (2, 4, 6, 8, and 12 hours). After the heat treatment of the specimens was completed, their moisture contents at relative humidity (RH) conditions of 45, 55, 65, 80, and 95%, their dimensional stabilities, their mechanical properties, e.g., bending strength, modulus of elasticity, and compression strength, were determined. Th e data obtained were analyzed using variance analysis, and then the statistical analysis of Tukey's test was conducted. Th e results showed that heat treatment resulted in decreased (i.e., improved) moisture content, enhanced dimensional stability, and reductions of the mechanical properties. Th e decrease of mechanical properties that resulted from the 12-hour test was greater than the reductions observed for the tests that lasted 2, 4, 6, and 8 hours.

Ethyl. n-propyl, and n-butyl isocyanates reacted with wood without catalyst to yield modified southern pine that was 30 to 50% more dimensionally stable than unmodified specimens and that had improved decay resistance. Phenyl and p-tolyl isocyanates and 1.6-diisocyanatohexane, isophorone diisocyanate, and tolylene-2.4-diisocyanate formed nonbonded polymers in wood voids and did not increase dimensional stability. In the presence of 35% dimethylformamide, however, n-butyl and phenyl isocyanates, 1,6-diisocyanatohexane and tolylene-2,4-diisocyanate reacted with wood, resulting in increased dimensional stability. The best dimensional stability and decay resistance of all specimens tested were shown by those modified with n-butyl isocyanate in the presence of 35% dimethylformamide. The dimensional stability was 70% better than that of unmodified specimens and the weight lost in the decay test was 2%, indicating a high resistance to decay.

Ethyl. n-propyl, and n-butyl isocyanates reacted with wood without catalyst to yield modified southern pine that was 30 to 50% more dimensionally stable than unmodified specimens and that had improved decay resistance. Phenyl and p-tolyl isocyanates and 1.6-diisocyanatohexane, isophorone diisocyanate, and tolylene-2.4-diisocyanate formed nonbonded polymers in wood voids and did not increase dimensional stability. In the presence of 35% dimethylformamide, however, n-butyl and phenyl isocyanates, 1,6-diisocyanatohexane and tolylene-2,4-diisocyanate reacted with wood, resulting in increased dimensional stability. The best dimensional stability and decay resistance of all specimens tested were shown by those modified with n-butyl isocyanate in the presence of 35% dimethylformamide. The dimensional stability was 70% better than that of unmodified specimens and the weight lost in the decay test was 2%, indicating a high resistance to decay.

Impressions are important sources of cross contamination between patients and dental laboratories. As a part of infection control impressions contaminated with variety of micro-organisms via blood and oral secretions should be cleaned and disinfected or sterilized before being handled in dental laboratory. The purpose of this study was to determine the effect of autoclaving on dimensional stability of elastomeric impression material (polyvinyl siloxane-Affinis). In this in vitro study standardized stainless steel die as per ADA specification number 19 was fabricated. Polyvinyl siloxane (Affinis) light body and putty viscosity elastomeric impression materials were used. A total of 40 impressions of the stainless steel die were made and numeric coding system was used to identify the samples. Measurements were made using a measuring microscope. Distance between the cross lines CD and C 0 D 0 reproduced in the impression were measured before autoclaving, immediately after autoclaving and 24 hours after autoclaving and dimensional change was calculated. The data obtained was subjected to statistical analysis. The mean difference in dimensional change between the three groups was not statistically significant (P [ 0.05). However the results revealed that there was higher mean dimensional change immediately after autoclaving when compared to the other 2 time intervals. It is desirable to delay the casting of an autoclavable elastomeric impression material by about 24 hours. Though disinfection of impression is routinely followed autoclaving of impression is an effective method of sterilization.